Dynamic bearing manufacturing method

ABSTRACT

A dynamic bearing manufacturing method including steps as follow. A plate is provided and a plurality of grooves is formed on a surface of the plate. The plate formed with grooves is rolled into a hollow cylinder. The grooves are located on the inner surface of the hollow cylinder, and thus to reduce cost of manufacturing process.

This Non-provisional Application claims priority under U.S.C. § 119(a) on Patent Application No(s). 094128354, filed in Taiwan, Republic of China on Aug. 19, 2005, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The invention relates to a method for producing a dynamic bearing, and in particular to a method for forming grooves on a plate, and following the plate being rolled into a cylindrical bearing.

In general, a dynamic bearing for supporting a shaft of a motor provides several miniature grooves formed on an inner wall thereof for receiving oil. When the shaft is rotated, oil received in the grooves spreads over the surface of the shaft by attraction force to form a dynamic pressure to support the shaft at the center of the dynamic bearing. Thus, friction between the shaft and the inner wall of the bearing and noise can be reduced and reliability of the motor can be increased.

However, forming grooves with desired width and depth on the inner wall of the bearing is not easily controlled. Some methods, such as tooling, rolling, plastic injection molding, erosion, assembling and coating with post-manufacturing, require high skill and precision and cost more than traditional methods, particularly when trade secrets are involved.

The invention provides a method for producing a dynamic bearing without using above described particular tools and machines so as to reduce manufacturing costs.

SUMMARY

The invention provides a dynamic bearing manufacturing method including steps as follow. A plate is provided and a plurality of grooves is formed on a surface of the plate. The plate formed with grooves is rolled into a hollow cylinder. The grooves are located on the inner surface of the hollow cylinder, and thus the cost of the manufacturing process can be reduced.

The plate prepared for the bearing is characterized by a predetermined size, circumferential length and axial hole. The plate is preferably made of flexible materials such as copper, metal or plastic. If the plate is made of metal, the grooves can be formed by a tool slitting the surface thereof, or the grooves can be pressed by a punch machine. If the plate is made of plastic, the grooves of the plate can be formed by injection molding.

The dynamic bearing is usually disposed within an axial hole of a sleeve. On the other hand, a sleeve can be formed by a plurality of separable parts, and thus the dynamic bearing can be enclosed by the assembled parts.

DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a schematic view of an embodiment of a plate for a dynamic bearing of the invention.

FIG. 2 is a schematic view of the processed plate of FIG. 1, wherein the processed plate is formed with grooves.

FIG. 3 is a schematic view of a hollow cylinder, where the hollow cylinder is a dynamic bearing formed by the processed plate of FIG. 2.

FIG. 4 is a schematic view of a sleeve, receiving the dynamic bearing of FIG. 3.

FIG. 5 is a schematic view of the dynamic bearing clamped by the sleeve, wherein the sleeve is formed by a plurality of separable parts.

FIG. 6 is a schematic view of another embodiment of a plate for a dynamic bearing of the invention.

FIG. 7 is a schematic view of the processed plate of FIG. 6, wherein the processed plate is formed with grooves.

FIG. 8 is a schematic view of another processed plate formed with grooves having a shape of herringbone.

DETAILED DESCRIPTION

In FIG. 1, a rectangular plate 1, preferably made of flexible materials such as copper, metal or plastic, is prepared for a bearing characterized by a predetermined size, circumferential length and axial hole. In FIG. 2, the processed plate is formed with a plurality of grooves 10 having a shape of fish bone or can be formed to have other shapes. Note that the grooves 10 of the metallic plate 1 can be formed by a tool slitting the surface thereof, or the grooves can be pressed by a punch machine. If the plate 1 is made of plastic, the grooves 10 of the plate 1 can be formed by injection molding.

In FIG. 3, by rolling the processed plate 1 into a hollow cylinder 1, a dynamic bearing 2 can be formed. The dynamic bearing 2 has an inner hole 20 to receive a shaft (not shown in Figs.), and the grooves 10 are formed on a wall of the inner hole 20.

In FIG. 4, the dynamic bearing 2 is usually disposed within an axial hole 30 of a sleeve 3. In FIG. 5, a sleeve 4 is formed by a plurality of separable parts 4 a and 4 b, and thus the dynamic bearing 2 can be enclosed by the assembled parts 4 a and 4 b.

The feature of the invention is that the grooves are pre-formed on the surface of the plate, and then the plate formed with the grooves is rolled into a hollow cylinder, i.e., a dynamic bearing. As the result, no particular tools machines are required, and cost can be reduced. Additionally, it is to be understood that the shape of the plate 1 is not limited to the above-disclosed embodiments. In a preferred embodiment, the plate can be formed into the shape shown in FIG. 6, or the plate can be formed into any shape where the ends thereof can be connected to each other during the rolling process. The grooves 10 can also be formed to have different shapes such as boomerang (FIG. 7), herringbone (FIG. 8), slanted line or straight line.

While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 

1. A dynamic bearing manufacturing method, comprising steps of: providing a plate; forming a plurality of grooves on a surface of the plate; and rolling the plate into a hollow cylinder, wherein the grooves are located on the inner surface of the hollow cylinder.
 2. The method as claimed in claim 1, wherein the plate comprises copper, metal or plastic.
 3. The method as claimed in claim 1, wherein the plate comprises two ends engaged to each other.
 4. The method as claimed in claim 1, wherein each of the grooves has a shape of fish bone, herringbone, boomerang, slanted line or straight line.
 5. The method as claimed in claim 1, wherein the grooves are formed by a tool slitting the surface of the plate, or the grooves are pressed by a punch machine, or the grooves are formed by injection molding.
 6. The method as claimed in claim 1, wherein the hollow cylinder is disposed within a sleeve after the step of rolling the plate.
 7. The method as claimed in claim 6, wherein the sleeve comprises an axial hole, and the hollow cylinder is disposed within the axial hole of the sleeve.
 8. The method as claimed in claim 6, wherein the sleeve is formed by a plurality of separable parts.
 9. The method as claimed in claim 8, wherein the separable parts for enclosing the dynamic bearing are assembled into the sleeve.
 10. A dynamic bearing manufacturing method, comprising steps of: providing a plate having two corresponding ends capable of connecting to each other; forming a plurality of grooves on a surface of the plate; and connecting the two corresponding ends to each other to form the dynamic bearing.
 11. The method as claimed in claim 10, wherein the dynamic bearing comprises an inner hole, and the grooves are formed on a wall of the inner hole.
 12. The method as claimed in claim 10, wherein the plate comprises copper, metal or plastic.
 13. The method as claimed in claim 10, wherein each of the grooves has a shape of fish bone, herringbone, boomerang, slanted line or straight line.
 14. The method as claimed in claim 10, wherein the grooves are formed by a tool slitting the surface of the plate, or the grooves are pressed by a punch machine, or the grooves are formed by injection molding.
 15. The method as claimed in claim 10, wherein the dynamic bearing is disposed within a sleeve after the step of connecting the two corresponding ends to each other to form the dynamic bearing.
 16. The method as claimed in claim 15, wherein the sleeve comprises an axial hole, and the dynamic bearing is directly disposed within the axial hole of the sleeve.
 17. The method as claimed in claim 15, wherein the sleeve is formed by a plurality of separable parts.
 18. The method as claimed in claim 17, wherein the separable parts for enclosing the dynamic bearing are assembled into the sleeve. 